Separated laravel app to its own folder (#540)

api/app/Rules/OneEmailPerLine.php

@@ -0,0 +1,58 @@
+<?php
+
+namespace App\Rules;
+
+use Closure;
+use Illuminate\Contracts\Validation\ValidationRule;
+
+class OneEmailPerLine implements ValidationRule
+{
+    /**
+     * Create a new rule instance.
+     *
+     * @return void
+     */
+    public function __construct()
+    {
+        //
+    }
+
+    /**
+     * Determine if the validation rule passes.
+     *
+     * @param  string  $attribute
+     * @param  mixed  $value
+     * @return bool
+     */
+    public function passes($attribute, $value)
+    {
+        if ($value === null || empty(trim($value))) {
+            return true;
+        }
+        foreach (preg_split("/\r\n|\n|\r/", $value) as $email) {
+            $email = trim($email);
+            if (! filter_var($email, FILTER_VALIDATE_EMAIL)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    public function validate(string $attribute, mixed $value, Closure $fail): void
+    {
+        if(!$this->passes($attribute, $value)) {
+            $fail($this->message());
+        }
+    }
+
+    /**
+     * Get the validation error message.
+     *
+     * @return string
+     */
+    public function message()
+    {
+        return 'You need one valid email per line.';
+    }
+}